The lack of clean drinking water in many rural communities throughout the world is a significant human-health concern. Point-of-use (POU) water purification offers an affordable and convenient way to reduce exposure to pathogenic microorganisms (Clasen, 2010). Paper-based filters coated with biocidal agents are easy to produce and distribute to remote locations. Filters containing nanoparticles do not require energy inputs for water purification. Paper and cotton fabrics are very abundant and regularly used in water filtration. Recently, for POU applications, we have designed a paper sheet embedded with silver nanoparticles to purify drinking water contaminated with bacteria (Dankovich and Gray, 2011a). As a more affordable alternative to silver, researchers have turned to using copper to purify drinking water (Sudha et al, 2012; Stout and Yu, 2003; Varkey and Dlamini, 2012).
Copper and copper compounds have been demonstrated to eliminate a wide variety of microorganisms, including Vibrio cholerae, Shigella, E. coli, Salmonella, fungi, viruses, and other types (Sudha et al, 2012; Esperito Santo et al, 2011; Molteni et al, 2010). Metallic copper surfaces have been used to prevent bacterial growth in hospitals (Esperito Santo et al, 2011; Molteni et al, 2010). Copper nanoparticles can be incorporated into fibrous materials to act as a long-lasting reservoir of copper ions for enhancing antimicrobial and catalytic activity (Vainio et al, 2007; Bendi and Imae, 2013; Ben-Sasson et al, 2013). Recently, researchers have demonstrated the application of copper nanoparticles to cellulosic materials (Vainio et al, 2007; Bendi and Imae, 2013; Jia et al, 2012; Cady et al, 2011). However, none of these researchers have evaluated these copper nanoparticle membranes as antibacterial drinking water purifiers. A similar membrane technology is a membrane containing copper oxide particles for virus removal from breast milk (Borkow et al, 2007). Recently, a related application using a porous ceramic substrate doped with copper nanoparticles as a filter material showed strong bactericidal activity (Klein et al, 2013).
There is a long felt need in the art for compositions and methods useful for making filters that can be used to purify or decontaminate water. The present invention satisfies these needs.